Adding roles for admin user
Adding roles for admin user

Rights missing to perform system.version actions:
```> db.system.version.remove({})
WriteResult({
	"writeError" : {
		"code" : 13,
		"errmsg" : "not authorized on admin to execute command { delete: \"system.version\", deletes: [ { q: {}, limit: 0.0 } ], ordered: true }"
	}
})```
dokku/dokku-mongo,dokku/dokku-mongo